Two Hamas suicide bombers killed at least 15 people in attacks yesterday on a busy Jerusalem cafe and on soldiers at a crowded bus stop near Tel Aviv. The blasts came just days after the Islamic organisation had said that the Israeli prime minister, Ariel Sharon, had "opened the gates of hell" by targeting its leaders for assassination.

Members of Israel's security cabinet were meeting last night to decide how to respond to the attacks, with one official saying that some form of military strike was inevitable.

The explosion in west Jerusalem ripped through a popular nightspot after a security guard challenged the bomber outside a cafe. At least seven people were killed.

Hours earlier, another bomber, possibly disguised as a soldier, killed eight people and left several more fighting for their lives after he mingled with dozens of soldiers at a crowded bus stop outside one of Israel's largest military bases at Assaf Ha Rofeh, south of Tel Aviv. Most of the victims were believed to be troops although the stop also serves a neighbouring civilian hospital.

Hamas claimed responsibility for both attacks. "We say to the Zionists it is payback time for your daily crimes against Palestinians," it said.

After the first blast, Ahmed Qureia, nominated to be the next Palestinian prime minister, immediately condemned the bombing. "We condemn all acts of killing that target innocents, whether they be Palestinians or the Israelis who were the victims of today's explosion," he said.

Neither blast was especially large by the grisly standards of the conflict here. But the impact is likely to be acutely felt as Israel makes good on its threat to "liquidate" the Hamas leadership, and in the midst of the political crisis in the Palestinian Authority.

The Jerusalem blast occurred shortly before midnight in an area of town popular with young people for its late night cafes and bars.

"Everything went black," said Mike Kovach, who was sitting in a neighbouring cafe. "Then there was an incredible amount of screaming and some people were running and some were stumbling about and some just lay there. It really was hell."

Another witness said he looked up after the blast to see a head lying in the street. A few feet away were two bodies underneath the cafe's shredded awning.

In the Assaf Ha Rofeh blast, the bomber targeted a crowd of soldiers waiting at a bus stop outside their military base. Eyal Schneider, a paratrooper who was treated for shock after being caught on the edge of the blast, said: "We were heading to the bus stop and we were just at the foot of the bridge when I heard the explosion. All I could hear was women screaming. There was smoke everywhere."

The bomber mixed nuts and bolts with explosive, producing horrific injuries. Pieces of metal, warped by the force of the explosion, were scattered among shards of flesh and a leg left behind long after the bodies of the victims had been removed, possibly because it belonged to the bomber.

"Some of those who survived have terrible injuries from the shrapnel," said Dr Ido Katz, deputy director of the Assaf Ha Rofeh hospital opposite the site of the attack. "We are dealing with multiple trauma, injuries to the head and face."

Israelis had been braced for the bombings for three weeks after Hamas threatened revenge for the assassination of Ismail Abu Shanab, one of the four highest leaders of the Islamic resistance movement. The likelihood of some form of retaliation grew after the Israeli army's botched attempt last week to kill Hamas' spiritual leader, Sheikh Ahmed Yassin, who had previously been considered untouchable.

Mr Sharon said Hamas leaders were "marked for death" after the worst bus bombing of the past three years of intifada, when 22 people died in an attack on ultra-Orthodox Jews in Jerusalem in mid-August.

The Israeli army has killed at least 12 Hamas activists in targeted assassinations since the bus bombing. Yesterday, the military shot dead a man it described as a Hamas commander in Hebron, Ahmed Badr, after a violent standoff which also saw a 13-year-old boy die from wounds inflicted by an Israeli tank shell.

The attacks will fuel pressure on Mr Sharon from some ministers to drive the Palestinian president, Yasser Arafat, into exile on the grounds that he is blocking the Palestinian Authority from combating "terrorist organisations". It may also provoke further Israeli incursions into the Gaza strip, the Hamas stronghold.